RNA helicases utilize the energy from ATP hydrolysis to unwind RNA. Some of them unwind RNA with a 3' to 5' polarity , other show 5' to 3' polarity . Some helicases unwind DNA as well as RNA [7,8]. May be identical with EC 3.6.4.12 (DNA helicase).
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SYSTEMATIC NAME
IUBMB Comments
ATP phosphohydrolase (RNA helix unwinding)
RNA helicases utilize the energy from ATP hydrolysis to unwind RNA. Some of them unwind RNA with a 3' to 5' polarity [3], other show 5' to 3' polarity [8]. Some helicases unwind DNA as well as RNA [7,8]. May be identical with EC 3.6.4.12 (DNA helicase).
RNA helicases are RNA-binding proteins able to resolve secondary and tertiary RNA structures in an active manner, in some cases coupling this enzymatic activity to the hydrolysis of ATP. Upon enzyme loading, the RNA helicase is able to locally open the RNA duplex facilitating the formation of a single-stranded structure. The proposed model for the catalytic activity of this group of RNA helicases suggests that the hydrolysis of ATP occurs before the strand separation. ATP hydrolysis is essential for the efficient release of the free enzyme from the RNA. The process is performed locally without any displacement of the enzyme along the RNA strands. Some proteins harboring helicase domains are able to recognize specific patterns in RNA molecules, bind to them and act as a skeleton to build ribonucleoprotein complexes without a specific catalytic activity over the RNA secondary structures
RNA helicases are RNA-binding proteins able to resolve secondary and tertiary RNA structures in an active manner, in some cases coupling this enzymatic activity to the hydrolysis of ATP. Upon enzyme loading, the RNA helicase is able to locally open the RNA duplex facilitating the formation of a single-stranded structure. The proposed model for the catalytic activity of this group of RNA helicases suggests that the hydrolysis of ATP occurs before the strand separation. ATP hydrolysis is essential for the efficient release of the free enzyme from the RNA. The process is performed locally without any displacement of the enzyme along the RNA strands. Some proteins harboring helicase domains are able to recognize specific patterns in RNA molecules, bind to them and act as a skeleton to build ribonucleoprotein complexes without a specific catalytic activity over the RNA secondary structures
the RNA helicase ubiquitous group of proteins is found in all the kingdoms of life, ranging from viruses to mammals, and it is closely related to DNA helicases. RNA helicases are included in five of the six nucleic acid helicase superfamilies. RNA helicases belonging to superfamilies SF3, SF4, and SF5 are oligomeric proteins (mostly hexamers), being typically encoded by genomes of viruses or bacteria. Superfamilies SF1 and SF2 of RNA helicases are non-oligomeric proteins, containing a conserved bi-lobular core composed by two RecA-like domains as a central structure. Several sub-families of RNA helicases are also defined on the basis of their sequence conservation and biological activity. Human RNA helicases are included in five different sub-families: Upf1-like, DEAD-box, DEAH-RHA, RIG-I like and Ski2-like proteins. The Upf1-like sub-family belongs to the SF1 superfamily, and includes a group of enzymes involved in RNA metabolism centered in processes like splicing or nonsense-mediated decay. The SF2 superfamily includes five different sub-families of RNA helicases: DEAD-box helicases, DEAH-RHA helicases, RIG-I like proteins, Ski2-like proteins and the NS3/NPH-II subfamily. SF1 and SF2 RNA helicases have other variable accessory domains located around their structural cores which frequently contain specific additional functionalities such as DNA-binding, protein-binding or oligomerization. Structure-function relationships of the most widely-studied families of RNA helicases: the DEAD-box, RIG-I-like and viral NS3 classes, overview. Enzyme NS3 falls within NS3/NPH-II subfamily of SF2 helicase superfamily
RNA helicases are involved in many biologically relevant processes, not only as RNA chaperones, but also as signal transducers, scaffolds of molecular complexes, and regulatory elements. Cells require either the presence of controlled chemical environments or the assistance of specialized proteins to ensure the stabilization and proper RNA folding. RNA chaperones or RNA helicases help RNA to reach and maintain its functional conformational state. Some of these RNA helicases are chaperone-like proteins that prevent RNA to reach energy minima characterized by an incorrect conformational state during folding. Others are correctors of misfolded RNAs, able to resolve incorrect structural elements and to produce single stranded RNA
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CRYSTALLIZATION (Commentary)
ORGANISM
UNIPROT
LITERATURE
hanging-drop vapor diffusion method, the 1.8 A crystal structure of the helicase region of the YFV NS3 protein (includes residues 187 to 623) and the 2.5 A structure of its complex with ADP